How To Replace BMW F30 Spark Plugs & Ignition Coils (BMW N20/N26 Engine)

Every engine needs fuel, air, and spark to run. The BMW's N20/26 engines have a spark plug and ignition coil for each cylinder. Failing plugs or coils will produce a weakened spark at best, resulting in poor ignition of the fuel/air mixture in the cylinder. Without the spark, the engine will make significantly less power while sounding and feeling poor. This BMW engine, because it has four cylinders, will throw a P0300-P0304 code when the engine computer determines a fault with a specific cylinder's spark.

Even though the spark plugs and ignition coils play a critical role in how an engine performs, they are fairly easily accessible and require a few hand tools to be replaced. The cost of parts is relatively cheap, and you'll gain valuable wrench-turning experience servicing the ignition on your own. 

 

BMW models and years applicable:

2014-2016 BMW 228i Incl. xDrive models	2014-2016 BMW 428i Incl. xDrive and GranCoupe models
2012-2016 BMW 528i Incl. xDrive models	2012-2016 BMW 328i Incl. xDrive and GT models
2015 BMW X4 xDrive28i	2012-2016 BMW Z4 sDrive28i
2013-2015 BMW X1  xDrive28i and sDrive28i	2013-2016 BMW X3  xDrive28i and sDrive28i

 

Symptoms of failing spark plugs and ignition coils on a BMW F30:

• Misfiring engine
• Reduced engine performance
• Trouble starting the vehicle
• Reduced fuel economy
• Engine backfiring
• Check engine codes

Any lack of spark can also leave raw fuel in the cylinder. The unburnt fuel can clean the cylinder walls of the thin layer of lubricating oil, potentially causing the piston rings to scratch the cylinder bores. Scored cylinder walls will lead to an excess in oil consumption and will cost exponentially more to fix than servicing the ignition system.

To ensure that your ignition components are performing as they should, replace them every 100,00 miles or so. If you are pushing more power through your engine from any modifications, cut the service interval in half.

 

What will it cost to replace the ignition coils and spark plugs on an N20/N26 powered F30 BMW?

The ignition service kit we put together comes with all you'll need for this job. You'll get four Delphi ignition coils and four NGK spark plugs, and the kit will run you around $150. Additionally, you'll need a spark plug socket for BMWs. We sell the correct Socket with the attached extension for around $25. 

Also handy to have is BMW's genuine spark plug installation tool. This piece of rubber tubing allows you to hold and thread the spark plug into the cylinder head without tools. That will let you engage the thread in the head without forcing and cross-threading them. The tool will run you around another $25.

 

How long will it take to replace the ignition coils and spark plugs on an N20/N26 powered F30 BMW?

The most time-consuming part of the job is getting to the pump. You need to remove several plastic covers from the engine bay just to be able to access the ignition coils and spark plugs. Once you get to it, however, the replacement is straightforward. Set aside forty-five minutes to complete the fuel pump replacement.

 

Parts required to replace the ignition coils and spark plugs on your N20/N26 powered BMW F30:

• BMW Ignition Service Kit

 

Tools required to replace the ignition coils and spark plugs on your N20/N26 powered BMW F30:

• 10mm Socket
• BMW Spark Plug Socket
• E18 Socket
• Ratchets
• Ratchet Extensions
• Torque Wrench
• Flathead Screwdriver
• BMW Spark Plug Installation Tool

 

Steps required to replace the ignition coils and spark plugs on your N20/N26 powered BMW F30:

Step 1: Expose the fuel pump

Grip the front of the engine cover and pull up to pop it off of the front locating pins. Then grab it by the right side and pull up to pop it off of the last pin. The pre-2013 engines also have two vacuum lines on the passenger's side of the cover that need to be disconnected before you can remove the cover.    

Underneath the plastic engine-cover is a foam noise-reduction pad. Pull up on it to remove it from the engine. Then move to the engine cowl. Use a 10mm socket to rotate the fasteners at the back of the cowl, a quarter turn. Then, remove the plastic rivets, securing them near the fenders. 

Removing those forward cowl pieces exposes the strut brace. Remove the two plugs from the rear cowl's center to reveal the strut brace's firewall mounting bolts. Then, pull the rubber strut covers off and remove the bolts with an E18 socket and pull the brace out. You need to remove a plastic rivet to remove each strut cover.

After that, remove the cover that sits below the brace. Use a 10mm socket to remove its seven bolts.

 

Step 2: Replace the ignition coils and spark plugs

Lift the lock on the ignition coil and disconnect the ignition harness. Then, pull up on the lock and pull the ignition coil out of the spark plug tube. 

After that, use the BMW spark plug socket to remove the spark plug from the cylinder head.

Remove all of the spark plugs and ignition coils before continuing. Then, place the new spark plug into the rubber installation tool and thread it into the cylinder head. 

Use the spark plug socket to torque all of the new plugs to 23Nm. Then, fit the new ignition coils over the freshly torqued plugs. 

Push the coils down until they bottom out. After that, plug the ignition harness into the coils and lock them into place. 

 

Step 3: Refit the engine bay plastics

First up, refit the noise insulation pad back to the valve cover. Slide it under the two tabs at the back for the engine cover, and then press the rest into place. 

Then, refit the lower cowl piece. Thread in its seven fasteners by hand before using a 10mm socket to tighten them. 

After that, install the strut tower brace. Line it up and loosely thread in all of the bolts by hand to ensure you've lined it up properly. Then, use an E18 socket to drive in and torque the bolts to 56Nm, plus 90° of rotation.

Next, reinstall the two upper cowl pieces. Slide them into place and use a 10mm socket to turn the three locks and secure the pieces to the car. Then refit the plastic rivets on their outer edges. 

Now you can refit the hood seal to the strut brace and run the cable through it. Then, refit the rubber strut covers and secure them with their plastic rivets.

Lastly, refit the engine cover. Reconnect the vacuum lines to the cover if your engine requires it. 

 

BMW F30 Ignition System Torque Specs:

• BMW Spark Plugs = 23Nm or 17 ft-lbs, of torque
• BMW Strut Brace Bolts = 56Nm or 41.3 ft-lbs, of torque

Servicing the ignition on your BMW is critical to keeping the engine running at its peak performance. If you're interested in more DIYs for your BMW, you can visit bmw.fcpeuro.com and subscribe to our YouTube channel.

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Written by :

Christian Schaefer

Car and motorsports-obsessed writer/editor for FCP Euro's DIY Blog. Constantly dreaming of competing behind the wheel or searching for another project. Owner of a Subaru Forester XT and a Porsche 914.